This invention relates to laser apparatus.
The invention is particularly concerned with apparatus for determining the distance of a moving object from a particular area. For example, an aircraft often requires to determine its altitude with precision and sometimes the vertical profile of the terrain over which the aircraft flies is required. In northern regions of Canada, whiteout conditions are encountered and the pilot of an aircraft needs reliable information as to the vertical profile of the terrain before landing on an unknown, unprepared site, if he cannot obtain an adequate assessment by direct observation. Furthermore, accurate information is also required for mapping and survey operations from the air.